<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="bootstrap/css/bootstrap.css">
</head>
<body>

<div class="container">
    <!--实现导航功能需要加role=navigation 这个是在父类上写的-->
    <div role="navigation">
       <!-- nav是基类 其他的都是扩展类。-->
        <ul class="nav nav-tabs">
            <!--active是表示当前选择的那个导航-->
            <li role="presentation" class="active"><a href="#">12</a></li>
            <li role="presentation"><a href="#">12</a></li>
            <li role="presentation"><a href="#">12</a></li>
            <li role="presentation"><a href="#">12</a></li>
        </ul>
        <!--胶囊型 +两端对齐的-->
        <ul class="nav nav-pills nav-justified">
            <li role="presentation" class="active"><a href="#">2</a></li>
            <li role="presentation"><a href="#">2</a></li>
            <li role="presentation"><a href="#">2</a></li>
            <li role="presentation" class="dropdown">
                <a class="dropdown-toggle" role="button" data-toggle="dropdown">
                    guess
                    <span class="caret"></span>
                </a>
                <ul class="dropdown-menu">
                    <li><a href="#">1</a></li>
                    <li><a href="#">1</a></li>
                    <li><a href="#">1</a></li>
                </ul>
            </li>
        </ul>
    </div>

</div>
<script type="text/javascript" src="bootstrap/jquery-3.1.0.min.js"></script>
<script type="text/javascript" src="bootstrap/js/bootstrap.js"></script>

</body>
</html>